Another Iranian-American held in Iran, US newspapers report

A Dubai-based businessman has become the fourth Iranian-American to be arrested by Iran's security forces and imprisoned in Tehran, as the Islamic Republic begins implementing a nuclear deal struck with world powers, several U.S. newspapers reported Thursday.

The detention of Siamak Namazi, believed to be in his early 40s, comes as an Internet freedom group said a Washington-based Lebanese citizen recently disappeared while on a trip to Tehran. Iranian officials and state media have yet to comment on either case, though there's speculation that some in Iran want to negotiate a prisoner swap with the U.S. for others held in the Islamic Republic, like detained Washington Post reporter Jason Rezaian.

Namazi was arrested earlier this month while visiting a friend in Tehran, a family friend told The Washington Post. It was not immediately clear whether any charges have been brought against Namazi. The friend asked not to be identified.

The U.S. State Department declined to confirm Namazi's arrest.

"We're aware of recent reports of the possible arrest in Iran of a U.S. citizen. We're looking into these reports and don't have anything further to provide at this time," Michael Tran, a State Department spokesman, said late Thursday.

Namazi, the son of a former governor in the oil-rich Iranian province of Khuzestan, comes from a prominent Iranian family, which came to the United States in 1983 when he was a boy, according to The Washington Post.

Namazi's arrest - also reported by The New York Times and The Wall Street Journal - suggests that hard-liners in Iran could be trying to create tension with the United States in the wake of Iran's nuclear deal with world powers. That agreement reached earlier this year promises Iran relief from crippling economic sanctions in exchange for curbs on its nuclear program.

Iranian hard-liners are opposed to moderate President Hassan Rouhani's strategy of attempting to improve ties with the West. Internal domestic struggles over the direction of Iran appear to be intensifying ahead of February's parliamentary elections.

The Washington-based National Iranian American Council said it was troubled by reports of Namazi's arrest and denied suggestions that his family had a leadership role in the organization, through it acknowledged "Namazi has known members of NIAC's staff."

"NIAC is very concerned by the continued detention of multiple Iranian Americans by the Iranian government, and is deeply troubled by the reports that Mr. Namazi may also have been detained," it said.

The arrest of an unnamed Iranian American businessman was first reported by IranWire, an online publication, on Oct. 15.

According to The Wall Street Journal and The New York Times, Namazi is head of strategic planning at Crescent Petroleum Co. In the past few weeks, Iranian businessmen with links to foreign companies have been detained, interrogated and warned against becoming involved in economic monopolies controlled by Iran's powerful Revolutionary Guard, The Wall Street Journal reported, citing businessmen inside and outside of Iran. The Times quoted unnamed people close to Namazi.

An official at Crescent Petroleum, which is based near Dubai in the Emirati city of Sharjah, said he had no information and did not confirm Namazi's employment when reached by The Associated Press this week. He later referred questions to an outside public-relations firm that did not respond to requests for comment.

A consulting company in Iran with which Namazi previously had ties, Atieh Bahar, denied to AP that he had any ongoing role there. An official, who refused to be identified, said Namazi had not worked with the firm "for eight or 10 years."

Meanwhile, Lebanese citizen Nizar Zakka disappeared Sept. 18 while visiting Tehran for a state-sponsored conference, according to a statement issued by the Washington-based group IJMA3-USA, which advocates for Internet freedom across the Middle East. Zakka was last seen leaving his hotel in a taxi for the airport to fly to Beirut, but never boarded his flight, according to the statement signed by lawyer Antoine Abou Dib.

"We have filed several requests with the Lebanese Ministry of Foreign Affairs asking assistance in locating him, without success," the statement said. "We therefore respectfully ask the Lebanese Ministry of Foreign Affairs, the Lebanese Embassy in Tehran and the Iranian authorities to assist us in locating Mr. Zakka, and to confirm that he is safe and will soon be permitted to return home."

Calls to IJMA3-USA rang unanswered early Friday and a phone number for Abou Dib could not be immediately found. Why Iranian authorities would want to detain Zakka remains unclear, though The Wall Street Journal said he held permanent-resident status in the U.S.

The apparent arrests come after Rezaian was convicted by Iran's Revolutionary Court on charges including espionage, though there have been no details on the verdict or sentence. He was detained in July 2014 and has now been in detention longer than the 52 American diplomats and citizens who were held hostage in Iran for 444 days from late 1979 to early 1981.

Other Americans held in Iran include former U.S. Marine Amir Hekmati, who holds dual Iranian and American citizenship and was arrested in August 2011. Saeed Abedini, a pastor from Boise was convicted in 2013 of threatening Iran's national security by participating in home churches. The U.S. also says it has asked for the Iranian government's assistance in finding former FBI agent Robert Levinson, who went missing in 2007 while working for the CIA on an unapproved intelligence mission.

In August, Iranian state media began quoting officials discussing the possibility of swapping Americans detained in Iran for 19 Iranians held in the U.S. However, it's unclear whether that's been seriously discussed between Iranian and American officials.